AC Electrical Conductivity and Dielectric Properties of Perovskite (Pb,Ca)TiO₃Ceramic

Abstract

Pb1−xCaxTiO3 perovskite crystalline structure with x = 0, 0.2, 0.6, 0.7, and 0.8 were prepared by mixture method. The ac conductivity and dielectric properties of the studied bulk compositions have been investigated in the frequency range 1 × 10 3 5 × 10 6 Hz and temperature range 303473 K. The experimental results indicate that the ac conductivity σac(ω), dielectric constant ε ′ and dielectric loss ε ′′ depend on the temperature and frequency. The ac conductivity was found to obey the power law ω S with the frequency exponent S > 1 decreasing with increasing temperature. The present results are compared to the principal theories that describe the universal dielectric response behavior. Values of dielectric constant ε ′ and dielectric loss ε ′′ were found to be temperature and frequency dependent and the maximum barrier height Wm is calculated.

Ac Conductivity and Dielectric Studies of Polypyrrole Copper Zinc Iron Oxide Nanocomposites

“…Such field will cause some ordering or orientation in samples, the molecular dipoles cannot orient themselves at low temperature, when the temperature is increased the dipole orientation is facilitated and dielectric constant increases. The strong frequency dispersion of permittivity is observed in the low frequency region followed by a nearly frequency independent behaviour above 10 KHz .The peak in the graph can be attributed to strong relaxation contribution leading to high dielectric constants and therefore electronic and ionic polarizablity [12].The negative dielectric constant observed at some frequencies for some wt.percentage is due DOI: 10.9790/4861-0805028390 www.iosrjournals.org 86 | Page to its reduced plasma frequency and an induction effect. The magnitude of the negative dielectric constant and the resonance frequency are tunable by dopant type and doping composition.…”

Dielectric Response and Transport Properties of Pb2Sr2CaCu2O9 [Lead Strontium Calcium Copper Oxide]

“…The variation of \n" with the temperature corresponds to a thermally activated process. 17 The conduction mechanism can be explained by the correlated barrier hopping (CBH) model till 400 C. At higher temperatures \n" has temperature-independent behavior which can be explained by the quantum tunneling model. Hence it can be concluded that similar charge barriers are responsible for both conduction and relaxation process in the sample Pb 2 Sr 2 CaCu 2 O 9 .…”

“…Electrical behaviors of complex ionically conducting materials plotted as a function of frequency and¯rst reported by Jonscher 15,16 are known as universal dielectric response (UDR). 17 The investigations performed into electrical properties of ceramic composites at alternating currents have con¯rmed that current conduction within a certain frequency range is realized by hopping exchange of electrons. [18][19][20] The objective of the present work is to study the dielectric and electrical impedance properties of the sample Pb 2 Sr 2 CaCu 2 O 9 in the range of frequencies (42 Hz-1 MHz) at di®erent temperatures with a view to understand the conductivity mechanisms involved in this new material.…”

Analysis of X-ray structure, dielectric properties and AC conductivity of (4E)-2-amino-3-cyanobenzo[b]oxocin-6-one

“…At low temperature, the dipoles cannot orient themselves. When the temperature is increased the orientation of the dipoles is facilitated and this increases the value of orientational polarization, which leads to an increase of ε 1 with temperature [25,26].…”